Rheostat



Dec. 16, 1924. 1,519,621

A. A. KE NT Filed April 14, 1923 10 L w/1Z7 INVENTOR.

WWW BY kATTOR/VEY.

circuit of Patented Deca I924 UNITE STES ARTHUR ATWATER KENT, OFARD'MORE, PENNSYLVANIA.

annos'rar.

Application filed April 14, 1923. Serial No. 631,987.

To all whom it may concern:

Be it known that I, ARTHUR A'rwA'rEn KENT, a citizen of the UnitedStates, residin at Ardmore, county of Montgomery, and State ofPennsylvania, have invented certain new and useful Improvements inRheostats, of which the following is a specification.

My invention relates to adjustable resistances or rheostats utilizedgenerally in the electrical arts for varying or adjusting the resistanceof a circuit, and more particularly for varying the resistance of the afilament or hot cathode of an audion or other thermionic device or tube,such as utilized in the radio art.

In accordance with my invention, the rotatable handle, cap, knob oroperating member of the rheostat forms with the relatively stationarystructure or member a housing or casing within which are disposed theresistance conductor and the co-acting adjustable and movable contact.

In accordance with my invention, the rotatable member or structure ofthe rheostat is itself a cap, knob or handle within whose diametrallimits are disposed the resistance conductor and the co-acting contactstructure.

In accordance with my invention, in an arrangement of the characterabove described, the! resistance conductor, co-acting contact structureand rotatable member, which last in effect houses the resistanceconductor and its co-acting contact structure, are disposed on one sideof a relatively fixed or base member through which extends a shaft orother bearing member for the rotatable structure, and connections madebeneath such fixed member or base are effected both with the shaft orbearing member and, if suitable or desirable, a terminal of theresistance conductor.

My invention resides in rheostat structure of the character hereinafterdescribed and claimed.

For an illustration of one of the various forms my invention may take,reference may be had to the accompanying drawing, in

which:

Fig. 1 is a top plan view of structure embodying my invention.

Fig. 2 is aplan view, partly in section, of the structure shown in Fig.1.

Fig.3 is a vertical sectional view, parts in elevation taken on the line3-3 of Fig. 1

Fig. 4 is a vertical sectional view, parts in elevation,

Fig. 5 is a bottom plan view of the structure shown in Fig. 1.

Fig. 6 is a view, in plan, of the inside of the cap or handle structure.

Fig. 7 is a perspective view of the rheostat contact.

Referring tothe drawing, 1 is a base or relatively fixed member which,in the example illustrated, is the end closure of a casing having theside wall 2., preferably molded integral with the base 1, of anysuitable insulating material, as, for example, bakelite or condensite.The members 1 and 2 in the example illustrated form a hollow base orfixed member which may be provided with the integral lugs or ears 3forattachment to any suitable support, as by screws: extending throughthe holes in the lugs 3.

Upstanding from the upper or outer side of the base 1 are the concentricannular ribs or flanges 4t and 5, of which the outer rib 4 is preferablythe higher. Between the ribs 4 and 5 is formed the channel or annulargroove 6, in which is disposed the resistance wire or conductor 7 of anysuitable material, preferably bare, and in the form of a coreless helix,one end of which extends through the hole 8 in the base 1 and isconnected to the binding post 9, secured to the side wall 2. The otherend of the resistance wire 7 may extend through a hole 10 in the base 1and then be bent over or otherwise secured on the under side of base 1.

The cap, handle or knob 11, preferably molded of insulating material ofany suitable character, as bakelite or condensite, may have upon itsperiphery the grip ribs 12, the cap comprising a body portion andcircumferential downwardly extending flange 11 The diameter of the cap11 in the example illustrated is substantially that of the annular rib4, the side wall of the cap 11, the rib a, the base 1 and the body ofthe cap 11 forming in efi'ect a chamber a portion of the wall structureof which is the knob, handle or cap, which is rotatable.

Molded within the body of the cap 11. is

the metallic insert 13 constituting in efiect a bearing member or stubshaft, which extends through' a hole 14 in the base 1 into the chamberbeneath. Adjacent its lower end the shaft 13 is provided with thecirtaken on the line H of Fig. 1..

cumferential groove or notch 15, into which .extend the forked ends 16of the sheet metal connecting member 17, turned downwardly at its outerend and connected with and held by the binding post 18.' The member 17is preferably more or less resilient, exerting a downward force or biasupon the shaft 13, and therefore upon the entire movable structure orcap 11. Surrounding the shaft 13 is the boss or lug 19, integral withthe cap 11, and adjacent or against the boss 19 is disposed the centralportion 20 of the movable contact 21, whose outer end 22 engages andrides upon the resistance wire 7. lhe portion 20 of the contact member21 may have a downwardly extending flange portion 23, by which it issoldered or otherwise secured to and electrically connected with, theshaft 13, the downward bias upon the shaft 13 and cap 11 exertedby themember 17 serving to press the contactend 22 firmly against theconductor 7 in all positions to which the contact member 21 may berotated.

Upstanding from the base 1 and within the annular rib 5 is the lug 24,extending into the path of travel of the downwardly extending lug 25molded-integral with the cap 11, the members 24 and 25 serving to limitthe extent of rotation which may be imparted to the cap 11 and thecontact mem- -The cap or. knob may carry any suitable indicating meansfor informing the operator as to the relative position of the contactmember 21 upon the resistance conductor 7. In the example illustrated,this indicating means is a. depression 26, Fig. 1, in the cap 11, filledwith any suitable material of a color differing from the color of thecap 11.

While the cap or knob 11 is preferably or substantially of the samediameter as the annular rib 4, it may be of greater of" lesser diameter,and in such case?" the circumferential side 11 of the cap may extendbelow the upper surface of the rib 4 or its equivalent.

In the example of my invention herein illustrated and described, and bypreference, the peripheral flange 11 of thecap 11 bears directly uponthe fixed mem ber, as base 1, or, as illustrated, when the upstandingflange 4 is employed, the lower end of the cap flange 11 bears directlyupon the upper face of the flange 4. The tension of the spring orresilient member 17 is such that the downward force exerted upon thestub shaft 13 plauses the cap to bear upon the base 1 or ange 4, theopposing spring effect of the rheostat contact member 21' being suitablysmall to permit such bearing of the capupon the fixed member and yeteffect good contact with the resistance conductor 7.

While in the example herein illustrated and described the resistanceconductor 7 is carried by the base structure or fixed member, and theco-acting contact 21 is carried by the rotatable structure or cap, itwill be understood that these rheostat members may be reversed as totheir mountings, that is to say, the resistance conductor 7 may be fixedwith respect to and carried by the cap, while the co-acting contact maybe carried by or secured to the fixed member or base. Such reversedarrangement of the rhcostat conductor and its co-acting contact thoughcomprehended by the appended claims is not herein, specifically claimed,but is claimed in my co-pending application S01. No. 634,450, filedApril 25, 1923.

hat ll claim, is:

1. Rheostat structure comprising relatively rotatable base and cap,means on one of them bearing upon the other and having within it a.recess, whereby there is formed.

between the base and cap a substantially closed chamber, a resistancemember and a co-acting relatively movable contact member disposed withinsaid chamber, said contact member movable along said resistance memherin direct contact therewith, one of said members being fixed withrespect to said base and the other of said members being fixed withrespect to said cap.

2. Rheosta-t structure comprising relatively rotatable base and cap,said base having an upstanding annular flange forming with said cap achamber between said cap and base. a resistance member and a co-actingrelatively rotatable contact member disposed within said chamber, one ofsaid members being fixed with respect to said base and the other of saidmembers being fixed with respect to said cap, and means holding saidcontact and resistance members in direct contact with each other. 7

3. Rheostat structure comprising relatively rotatable base and cap, anannular membar on one of them enclosing a recess and bearing upon theother, whereby a sub stantially closed chamber is formed between saidcap and base, a resistance member and a. co-acting relatively movablecontact member disposed within said chamber, one of said members beingfixed with respect to said base and the other of said members beingfixed with respect to said cap, and means for holding said contact andresistance members in engagement with each other.

'1. Rheostat structure comp-rising relatively rotatable base and cap,said base having an upstanding annular flange, said cap having a flangeextending towards said base and bearing upon said flange upon said baseto form a chamber between said capand base, means biasing said base andcap toward each other, a resistance member and a coacting relativelyrotatable contact member disposed within said chamber, one of saidmembers being fixed with respect to said base and the other of saidmembers being fixed with respect to said cap.

ill

Y 5. Rheostat structure comprising relatively rotatable base and cap,said base having an upstanding annular flange, said cap having a flangeextending towards said base and disposed in end to end contact with saidflangeuppn said base to form a chamber between said cap and base, meansbiasing said base and cap toward each other,.a resistance member and aco-acting relatively rotatable contact member disposed within saidchamber, one of said members being fixed with respect to said base andthe other of said members being fixed with respect to said cap.

6. Rheostat structure comprising relatively rotatable base and capforming a chamber therebetween, a resistance member and a co-actingcontact member disposed within said chamber and rotatable relatively onealong the other in direct contact with each other, one of said membersbeing fixed with respect to said base and the other of said membersbeing fixed with respect to said cap, a member fixed on said capdisposed within said chamber, and a member fixed on said base co-actingwith said last named member to form a stop for limiting the extent ofrelative rotation of cap and base.-

7. Rheostat structure comprising relatively rotatable base and cap, saidbase having upstanding annular flanges spaced from each other to form achannel, a resistance conductor disposed in said channel between saidcap and base, and a contact secured to said cap and'movable along saidresistance conductor.

8. litheostat structure comprising relatively rotatable base and cap,said base having upstanding annular flanges spaced from each other toterm a channel, said cap, base and outer flange forming a chamber, aresistance conductor disposed in said channel within said chamber, and acontact movable along said resistance conductor and disposed within saidchamber and secured to said cap.

9. Rheostat structure comprising relatively rotatable base and cap, saidbase having upstanding annular flanges spaced from each other .0 formachannel, the outer of said flanges extending higher above said basethan the other of said flanges, said base, outer flange and said capformin a chamber, a resistance conductor dispose in said channel withinsaid chamber, and a co-acting contact secured to said cap within saidchamberand. extending across said other of said flanges into engagementwith said resistance conductor.

10. Rheostat structure comprising relatively rotatable base and capforming a chamber therebetween, a bearing shaft for said cap extendingthrough said base, a resistance member and a co-acting relativelyrotatable contact member disposed within said chamber, said contactmember secured to and connecting with said shaft, and means engaging theshaft on the opposite side of said base for biasing said cap and contactmember toward said base and resistance member.

11. Rheostat structure comprising relatively rotatable base and capforming a chamber therebetween, a shaft molded in said cap and extendingto the opposite side of said base, a resistance conductor disposed onsaid base Within said chamber, a co-acting contact secured to andelectrically connecting with said shaft, and means on said opposite sideof said base engaging said shaftand biasing said contact toward saidbase and said resistance conductor.

12. Rheostat structure comprising a casing having an end closureforminga base, a cap outside of said base rotatable with respect thereto, aresistance conductor disposed upon the outside of said base and enclosedby said cap, and a contact member secured to said cap and movable alongsaid resistance conductor in direct contact therewith. p

i3. Rheostat structure comprising a casing having an end closure forminga base a cap outside of said base rotatable with respect thereto, aresistance conductor disposed upon the outside of said base and enclosedby said cap, a contact member secured to said cap and movable along saidresistance conductor in direct contact therewith, and connections fromsaid resistance conductor and contact member extending through said baseinto said casing.

141. Rheostat structure comprising relatively rotatable base and cap,means on one of them bearing upon the other and having within it arecess, whereby there is formed between the base and cap a substantiallyclosed chamber, a resistance member and a co-acting relatively movablecontact member disposed within said chamber, one of said members beingfixedwith respect to said base and the other of said members being Ifixed with respect to said cap, and means holding said cap and base incontact with each other at said means and holding said contact member inengagement with said resistance member.

15. Rheostat structure comprising relatively rotatable base and cap,means on one of them bearing upon the other and having within it arecess, whereby there is formed between the base and cap a substantiallyclosed chamber, a resistance member and a (Io-acting relatively movablecontact member disposed within said chamber, one of said members beingfixed with respect to said base and the other of said members beingfixed with respect to said cap, and resilient means biasing said cap andbase into engagement with each other and holding said contact andresistance members in engagement with each other in opposition to thespring effect of their engagement.

16. Rheostat structure comprising relatively rotatable base and cap,said base having an upstanding annular flange, a resistance memberdisposed between said cap and base, a co-acting contact member, one ofsaid members being fixed with respect to said base and the other of saidmembers being fixed with respect to said cap, and means biasing said capinto contact with said annular flange and said resistance and Contactmembers into engagement with each other. 1

17. Rheostat structure comprising relatively, rotatable base and cap,said base having an upstanding annular flange, said cap having acircumferential flange extending toward said annular flange, aresistance member disposed between said cap and base,

a co-acting contact member, and means biasing'said flanges into contactwith each other and said members into engagement with each other.

18. Rheostat structure comprising relatively rotatable cap and base, oneof them having an axially extending projection engaging the other, asubstantially closed chamber formed between said cap, base andprojection, co-acting contact and resistance members disposed withinsaid chamber, one of said members secured to said cap and the other ofthem secured to said base, a shaft member for centering said cap andbase with respect to each other and secured to one of them and extendingloosely in an aperture in the other of them, and means for biasing saidcap" and base into engagement with each other at said projection.

19. Rheostat structure comprising relatively rotatable base and cap,said base and cap being unbiased with respect to each other regardingtheir relative rotation, means on one of them bearing upon the other andhaving within it a recess, whereby there is formed between the base andcap a substantially closed chamber, a resistance member and a co-actingrelatively movable contact member disposed within said chamber, saidcontact member movable along said resistance member in direct contacttherewith, one of said members being fixed with respect to said base andthe other of said members being fixed with respect to said cap, andmeans for biasing said cap and base toward each other and for holdingsaid resistance and contact members in contact with each other.

20. Rheostat structure comprising relatively rotatable base and cap,said base having an upstanding annular flange, a resistance memberdisposed between said cap and base, a co-a-cting contact member, one ofsaid members being fixed with respect to said base and the other of saidmembers being fixed with respect to said cap, a conducting membersecured to said cap and extending through said base, one of said memberselectrically connected to said conducting member, and means on the sideof said base opposite said cap engaging said conducting member to biassaid cap into engagement with said annular flange and said resistanceand contact members into contact with each other.

21. Rheostat structure comprising relatively rotatable base and cap,said base having an upstanding annular flange, said cap having acircumferential flange extending toward said annular flange, aresistance member disposed etween said cap and base, a co-acting cont ctmember, a conducting member secured to said cap and extending throughsaid base, one of said members electrically connected to said conductingmember, and means on the side of said base opposite saidcap engagingsaid conducting member to bias said flanges into engagement with eachother and said resistance and contact members into contact with eachother.

In testimony whereof I have hereunto affixed my signature this 10th dayof April, 1923.

ARTHUR ATVVATER KENT;

